Completed Javron Super Cub

[upnorth]

Would like to share my newly finished Javron Super Cub. My first build

Many thanks to Jay at Javron for building quality and taking my many phone calls.

Huge thanks to Will Luggar where plane was assembled and flown from his grass strip. He has rebuilt and repaired many planes and more recently a EX-3 build. Will is a A and P and showed me many things on my first build. I would highly recommend him to anyone looking to have one built or worked on as his level of craftsmanship is top notch.

So here are the specs for N517HW, first flight on May 13. Have 42hrs TT with phase 1 complete.

Narrow body PA-18
Titan 0-340 180hp
sensenich 82” ground adjustable
0 degree thrust mount
vg kit on wings and horizontal
stock wing, flaps,tail feathers and landing gear
31” bush wheels
overhead flap handle
covered and painted in Stewart’s system
carbon fiber plenum, floorboard and side panels
mgl asv-2, ems-2 and v-16 radio
Garmin 760 panel mounted navigation
Empty weight 1008 on 31s

Really light on the controls and flys hands off. Really performs

 

[rc dude]

Looks great! And nice empty weight too!

Do you have any pics of your plenum setup? Are they the Vetterman plenums or something custom?

 

[upnorth]

Thanks! Yes I used the vetterman plenum. It took some work to get the transition from nose bowl to plenum but it worked out great. Had to make a mold and then fiber glass the mold for the inlet ducts. My cht temps have been about 360f in 85f OAT

 

[DJ]

Sounds really light! Would you recommend the plenum? Are standard engine baffles a lot easier?

 

[Tgskillskill]

Thanks! Yes I used the vetterman plenum. It took some work to get the transition from nose bowl to plenum but it worked out great. Had to make a mold and then fiber glass the mold for the inlet ducts. My cht temps have been about 360f in 85f OAT

Just think how much lighter you could have been if you used carbon fiber vs. fiberglass. :lol:

 

[Grumman]

Congrats that is a great looking plane.


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[WWhunter]

I think I've seen that plane before!! Sweet plane bud!! But now that Will is famous, will he still be our friend? LOL

 

[Bugs66]

Very nice! Congrats!

 

[bcone1381]

Your creative transition from the nosebowl to the plenum is inspiring. This particular area is very well suited for composite construction and seems like an undiscovered EAB industry best practice.....superior to aluminum in speed to fabricate, and equipment needed to do a well crafted job, smoothing and sealing of airflow.

I had a Vetterman Plenum in my hand and did not understand (and did not remove barriers to discover) how it interfaces with the inboard cyliner area, and other questions. Could you share some photos with us how the plenum seals up and how you dealt with the necessary plenum penetrations like spark plug wires?

 

[Bill Rusk]

Fantastic empty weight!! Congratulations!!!!!

Bill

 

[upnorth]

Appreciate all the comments

I’ve never made baffling before so I’m not sure which one would be easier. I chose to use the plenum based on the cooling requirements needed for the 0-340. From everything I’ve read, they can run hot.

here are some photos of how the inlet ducts worked with the plenum.

 

[thaefeli]

Panel photos please. Sounds like what I have chosen for my 4S.
Tom

 

[Steve Pierce]

Nice work. How are your temps?

 

[upnorth]

Cht temps are really good but my oil temps on hot days run around 205. It’s fine for wheels but I don’t think it will be adequate for float operations that I plan on. I have a 3” scat pulling from the rear of the #4 bank to a firewall mounted oil cooler. I don’t really want to mess with that since my cht temps are so even a working good.
Hears a picture from last night of the MGL instruments working.Also gives idea of the temps. OAT about 65

 

[skywagon8a]

.... oil temps on hot days run around 205. It’s fine for wheels but I don’t think it will be adequate for float operations that I plan on. I have a 3” scat pulling from the rear of the #4 bank to a firewall mounted oil cooler. I don’t really want to mess with that since my cht temps are so even a working good.

Place a baffle tight against the rear of #4. Extend it up above the top of the cylinder with the upper part bent forward. This will block any heat from #4 going through the oil cooler and will capture cool air from above the engine, funneling the cool air directly into the oil cooler.

 

[Steve Pierce]

Cht temps are really good but my oil temps on hot days run around 205. It’s fine for wheels but I don’t think it will be adequate for float operations that I plan on. I have a 3” scat pulling from the rear of the #4 bank to a firewall mounted oil cooler. I don’t really want to mess with that since my cht temps are so even a working good.
Hears a picture from last night of the MGL instruments working.Also gives idea of the temps. OAT about 65

205 degree oil temp doesn't bother me but I guess you are afraid it will be higher on floats? The CHTs were the issues on the Cub Crafters airframes with the O-340. The bigger carburetor fixed it on the Legend airframes. CC had several different iterations to fix.

 

[Lasater]

My O-340 is running at 205 at cruise as well, but I can get it back to 195 or so at 2050 rpm. I have been concerned about 200 plus temps, but I don't know if it is a recent phenomenon or something I just missed. I misplaced the USB adapter for my engine monitor, so I am waiting for JPI to send me a new one before I can look at historic data.

If Steve isn't worried about 205 degrees, maybe I shouldn't worry either. CHT's are all less than 385 degrees. Rear mounted oil cooler, engine baffles and scat tube to oil cooler are intact. No obstructions in the oil cooler.

 

[JeffP]

My O-340 is running at 205 at cruise as well, but I can get it back to 195 or so at 2050 rpm. I have been concerned about 200 plus temps, but I don't know if it is a recent phenomenon or something I just missed. I misplaced the USB adapter for my engine monitor, so I am waiting for JPI to send me a new one before I can look at historic data.

If Steve isn't worried about 205 degrees, maybe I shouldn't worry either. CHT's are all less than 385 degrees. Rear mounted oil cooler, engine baffles and scat tube to oil cooler are intact. No obstructions in the oil cooler.

I am unsure what one would want for normal oil temps. Am I wrong in thinking I would want oil well over 200f to rid the crankcase of moisture?


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[Kid Durango]

I always used 180* as the magic number. It should get hotter as it gets circulated for the momentary heating and evaporating of any water.

 

[Lasater]

On the O-340, the redline is 245 degrees, but the manual says target 180 degrees.

 

[vj88]

Appreciate all the comments

I’ve never made baffling before so I’m not sure which one would be easier. I chose to use the plenum based on the cooling requirements needed for the 0-340. From everything I’ve read, they can run hot.

here are some photos of how the inlet ducts worked with the plenum.

Great weight and beatuiful cub.

I have a 370 with vans 360 baffling with 3” duct off of number 4 as well and get the same cht and oil temps. I run the whirlwind GA and have heard trying a different propeller may solve the hot oil temps. What are you thinking of trying to solve the oil temp?

 

[KevinJ]

I’m scratching my head trying to figure out how you got to 1008lbs on 31s and an electrical system. No Pstol flaps and the GA prop helps. From my understanding Jays alum struts aren’t much lighter than standard struts. 340 is a little lighter? What’d you cut out?

 

[RaisedByWolves]

I’m scratching my head trying to figure out how you got to 1008lbs on 31s and an electrical system. No Pstol flaps and the GA prop helps. From my understanding Jays alum struts aren’t much lighter than standard struts. 340 is a little lighter? What’d you cut out?

Maybe you can use his scales to weigh your new one


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[upnorth]

I’m scratching my head trying to figure out how you got to 1008lbs on 31s and an electrical system. No Pstol flaps and the GA prop helps. From my understanding Jays alum struts aren’t much lighter than standard struts. 340 is a little lighter? What’d you cut out?

It took a bunch of things to get there. Reading Many great tactics in this forum and Bill Rusks thread was incredibly helpful. I’ll try and break down what I can and maybe it will be helpful for someone.
On top of what I haven’t already mentioned.

carbon fiber prop and nose cone
carbon fiber nose bowl
hollow crank conical 0-340 with magnesium sump, emags, sky tech starter and sky dynamics ring gear.
veterman exhaust
Earthx battery
aero classic 8000081 oil cooler
titanium firewall
minimal electronic instruments
Seats have carbon fiber backs with minimal padding (probably going to change that)
Grove 1 1/4 magnesium wheels with drilled rotors
bungees on stock gear (changing to extended gear soon)
No headliner or cloth on side panels
carbon fiber baggage door
aluminum struts

I would say the two biggest savings were the 0-340 and the stock wings.
Titan gave me a factory weight of 256 pounds. I took off a few more with the sky dynamics starter gear.
Jays wings came pretty darn light as well.